Blow tube with removable flange

ABSTRACT

For economy, a blow tube is separated into a portion that wears quite readily, and another portion that is reusable. The duct portion that wears readily has a small flange that fits into a counterbore of a larger flange.

United States Patent [191 Mind ock [451 Aug. 20, 1974 BLOW TUBE WITH REMOVABLE FLANGE [76] lnventor: John R. Mindock, 2006 Terril Ln.,

Louisville, Ky. 40218 22 Filed: Dec.7, 1972 211 App]. No.: 312,872

[52] US. Cl. 164/200 [51] Int. Cl. B22c 15/24 [58] Field of Search 164/200, 19, 410, 397, 164/412 [56] References Cited UNITED STATES PATENTS 2,637,881 5/1953 Peterson 164/200 2,687,559 8/1954 Peterson 164/200 2,761,186 9/1956 Peterson 164/200 2,933,786 4/1960 Peterson.... 164/200 3,104,432 9/1963 Peterson.... 164/200 3,460,607 8/1969 Olson 164/200 Primary Examiner-J. Spencer Overholser Assistant Examiner-John S. Brown Attorney, Agent, or FirmHenderson & Strom 5 7 ABSTRACT For economy, a blow tube is separated into a portion that wears quite readily, and another portion that is reusable. The duct portion that wears readily has a small flange that fits into a counterbore of a larger flange.

3 Claims, 3 Drawing Figures BACKGROUND OF THE INVENTION This invention relates to blow tubes used in foundries to conduct a mixture of sand and thermosetting material into cavities of core boxes, and particularly to blow tubes with removable flanges to facilitate reuse of the flanges with new tubes.

A type of blow tube that is commonly used comprises a single piece turned from rod stock. Since the inlet end of the tube has a flange that is much greater in diameter than the remainder of the tube, much machining is required, and much of the stock from which the tube is being turned is made into scrap. Each tube is inserted through the blow plate of a core box and conveys a mixture of sand into the cavity of the box. The portion of the tube that extends through the box is exposed to the greater amount of abrasive action and soon becomes worn so that it has to be replaced. To reduce the amount of wear, cold rolled steel from which the tubes are fabricated may be treated with boron, or plastic inserts may be used to prevent wear on the main structure of the tube.

A tube with a removable, stainless steel liner is shown in US. Pat. No. 3,235,921 issued to Bego et al. on Feb. 22, I966. Compared with the simple blow tubes comprising merely a tubular portion and a flange, the blow tube in that patent has a cooling jacket such that the entire assembly is relatively complicated.

SUMMARY OF THE INVENTION The main tubular portion of the blow tube has only a small flange encircling the end of the tube used as an inlet. This tube compared with previous tubes made in one piece, is much less costly because the amount of material and the amount of machining are greatly reduced. To increase the effective size of the flange to bear against the upper surface of a blow plate, a larger flange encircles the integral flange of the tube. The larger flange has a central bore in which the tube fits into a counterbore for receiving the relatively small flange of the tubular portion. Since the separate flange outwears several relatively inexpensive tubes, the cost of supplying blow tubes in a foundry is reduced to only a fraction of the cost of providing one-piece tubes.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENTS The two-piece blow tube of this invention is shown in v FIG. I positioned through the upper plate or the blow plate 12 of a core box. The duct portion 13 of the blow tube is a tight fit in a hole of the blow plate 12, and preferably, the outer surface of about three-fourths of the lower portion of the tube is undercut 0.002 inch to facilitate driving the blow tube until the lower surface of the flange I4 is in contact with the upper surface of the blow plate 12. According to the usual arrangement, the space above the blow plate 12 is a reservoir for a mixture of sand and thermosetting material, and pressure is applied to the reservoir to force the mixture downwardly through the duct portion 13 to the cavity of a mold below the blow tube. The reservoir (not shown) may have holes registering with the blow tubes inserted in the blow plate 12 such that the mixture under pressure is directed into the inlet of the blow tube.

The parts of the blow tube 11 are fabricated from cold rolled steel stock. The outer wall of the duct portion 13 is substantially cylindrical except that the lower portion is undercut 0.002 inch as described above. The axial bore 17 of the duct portion 13 is tapered to diverge gradually from the inlet to the outlet to aid in preventing clogging of the blow tube by the mixture. The inner surface of the bore may be treated with boron to harden it against wear. The upper or inlet portion of the duct portion 13 has an integral flange 19 to fit in a larger flange 14.

As shown in FIG. 2, a generally disc-shaped flange 14 has a central bore 20 therethrough with an inside diameter that provides a sliding fit about the upper, outer wall 15 of the duct portion 13. The upper side of the flange 14 has a counterbore with the depth equal to the thickness of the integral flange 19 that encircles the inlet end of the duct portion 13. The inside diameter of the counterbore 21 is substantially equal to the outside diameter of the integral flange 19 so that the flange 19 is a sliding fit within the counterbore. The counterbore 21 provides a shoulder 22 on which the lower surface of the integral flange l9 rests when the blow tube is assembled such that the upper surfaces of the flanges l4 and 19 are even. Since the wear on the flange 14 is much less than the wear on the duct portion 13, the

flange 14 can be reused several times for similar new duct portions 13, and obviously, the flange can be used for duct portions of different lengths.

Compared with the blow tube described above, the blow tube 23 of FIG. 3 has the integral flange 26 of the duct portion 24 and the retaining flange 25 modified to accommodate a gasket 28. The duct portion 24 that extends through the blow plate 12 is similar to the duct portion 13 described previously, but the integral flange 26 about its inlet has its periphery modified in that it has been machined to provide an arcuate groove 27 facing outwardly. Before the duct portion 24 is placed completely within the retaining flange 25, a resilient gasket or O-ring 28 is placed in the peripheral arcuate groove 27. The counterbore 29 of the retaining flange 25 is greater in diameter than the diameter of the counterbore 21 of FIG. 2 to permit the gasket 28 to fit tightly between the groove 27 and the inside surface of the counterbore 29.

The height or diameter of the gasket 28 is somewhat greater than the depth of the counterbore 29 so that the surface of the gasket is normally slightly higher than the upper surfaces of the adjacent flanges. When the reservoir that has a hole registering with the bore of the duct portion 24 is pressed against the upper surfaces of the flanges 25 and 26, the gasket 28 is compressed until its surface is even with the surfaces of the flanges. When the blow tube is used to convey sand to the cavity of the mold, the gasket 28 aids in preventing lateral dispersion of the sand at the end of a cycle when the reservoir is removed from the blow plate 12.

Cost of maintenance in a foundry is reduced substantially by using in foundries two-piece blow tubes as described above. The duct of a blow tube wears much faster than the flange, and the duct portion with its small flange can be machined from smaller stock and readily replaced in the removable retaining flange. In addition to being used for conveying a mixture of sand and binder, the tubes may be used in other applications to convey either liquid or particulate material. The gasket 28, as shown in FIG. 3, adapts the tubes to new uses where a seal is required to prevent leakage between the source and the duct for conveying material from the source. When high temperatures are not encountered, the gasket 28 can be a usual O-ring fabricated from neoprene, and as required, plastics that withstand high temperatures can be provided for operations in foundries.

I claim:

1. A blow tube comprising:

a duct and a removable retaining flange, said duct having an inlet end and an outlet end for discharging material into a cavity of a container, said retaining flange encircling said inlet end to provide an annular surface of substantial area to bear against the outer surface of the container;

said duct being step cut to provide an integral flange encircling said inlet end, the distance that said integral flange extends outwardly from the outer surface of said duct being insufficient to provide a desired area to bear against the outer surface of the container;

said retaining flange having a bore therethrough of a diameter to provide a sliding fit about said inlet end of said duct adjacent said integral flange and having a counterbore in one face thereof opposite said surface to bear against the container, said integral flange fitting within said counterbore such that said duct extends through the wall of the container, said integral flange having a peripheral groove;

a resilient ring, said ring being somewhat thicker than the depth of said counterbore, and having a required inside diameter to fit tightly in said peripheral groove, and said counterbore of said retaining flange being of such diameter to receive tightly said ring encircling said integral flange, the surface of said ring normally extending beyond the outer surfaces of said flanges and being compressible against said outer surfaces of said flanges, and said duct being removable from said retaining flange which retaining flange is to be reusable with other ducts similar to said duct.

2. A blow tube as claimed in claim 1 wherein the outer wall thereof is undercut slightly over a substantial length thereof at the end opposite said integral flange to facilitate driving said duct when assembled in said retaining flange through a hole in a container.

3. A blow tube as claimed in claim 1 having a tapered, axial bore such that the diameter of the bore gradually diverges in a direction from said inlet end to said outlet end. 

1. A blow tube comprising: a duct and a removable retaining flange, said duct having an inlet end and an outlet end for discharging material into a cavity of a container, said retaining flange encircling said inlet end to provide an annular surface of substantial area to bear against the outer surface of the container; said duct being step cut to provide an integral flange encircling said inlet end, the distance that said integral flange extends outwardly from the outer surface of said duct being insufficient to provide a desired area to bear against the outer surface of the container; said retaining flange having a bore therethrough of a diameter to provide a sliding fit about said inlet end of said duct adjacent said integral flange and having a counterbore in one face thereof opposite said surface to bear against the container, said integral flange fitting within said counterbore such that said duct extends through the wall of the container, said integral flange having a peripheral groove; a resilient ring, said ring being somewhat thicker than the depth of said counterbore, and having a required inside diameter to fit tightly in said peripheral groove, and said counterbore of said retaining flange being of such diameter to receive tightly said ring encircling said integral flange, the surface of said ring normally extending beyond the outer surfaces of said flanges and being compressible against said outer surfaces of said flanges, and said duct being removable from said retaining flange which retaining flange is to be reusable with other ducts similar to said duct.
 2. A blow tube as claimed in claim 1 wherein the outer wall thereof is undercut slightly over a substantial length thereof at the end opposite said integral flange to facilitate driving said duct when assembled in said retaining flange through a hole in a container.
 3. A blow tube as claimed in claim 1 having a tapered, axial bore such that the diameter of the bore gradually diverges in a direction from said inlet end to said outlet end. 